Bleeding Fuel on M25XP

[womble]

Can anyone shed light on how to bleed my M25XP?
I have done this twice without issues but I would like someone to confirm things.
I have an electrical lift pump so I turn the key to start and get the fuel pump "ticking". I then open the knurled nut shown in the photo below which I am hoping is, in fact, the bleed valve. I have never seen any air or fuel escape from this nut but have never had an airlock!

https://1drv.ms/u/s!AoWQoXwAWrSh2g0G_z2QWhohf_5G

 

[Jongleur]

Yes, that is the bleed valve. You won't see
any air or fuel, because it allows such to
return to your tank. Brilliant system!

 

[Stu Jackson]

You don NOT want fuel to bleed from that valve "handle" which most of us call the "knurled knob."

Here's everything you need to know about it:

Bleeding 101 http://c34.org/bbs/index.php/topic,6377.0.html

Since you have an M25XP, try this, too:

Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too

http://www.c34.org/wiki/index.php?title=Diesel_Engine

No need to reinvent the wheel.

 

[womble]

There is simply way too much contradiction in the articles. Some say crack the knurled knob, you say don't. Some say use the bleed valve on the secondary filter - there is no valve on my secondary filter!!
If the knurled knob is not for bleeding - what is it for?

Here is a quote from one you the threads you kindly cited:
"The proper way to use the knurled knob: After changing your filters, open the knob fully. Activate the electric fuel pump by turning on the key (or jumper in some cases). The pump will rapidly click then eventually slow down when the air is out of the lines. Close the knurled knob, the pump should click every couple of seconds. If desired crack the knurled knob 1/4 to 1/2 turn. Engine start should then be normal."

To which YOU reply that the knurled knob IS used for bleeding!!!!

 

[Jongleur]

Womble:
Yes, it is a bleed valve. But it doesn't
allow fuel to come out where you can
see it. It allows fuel and air to be sent
back to your fuel tank. Go ahead and
use it to bleed your system.

 

[Stu Jackson]

There is simply way too much contradiction in the articles.

Not really. The only "contradiction" is that one skipper proposed to crack the knurled knob ALL THE TIME, to which many disagreed. As far as your OP is concerned, that IS what it is for. 99% of us keep it closed once bled.

You asked, I gave you a wealth of information.

And both ideas work.

 

[Stu Jackson]

Some say use the bleed valve on the secondary filter - there is no valve on my secondary filter!!

Just to add: There is a NUT on the top of the secondary (engine mounted) filter. THAT is what that means. I have found that I need to crack that nut when replacing the secondary filter, others have not.

Of course, this is NOT the knurled knob.

Maybe you should take a deep breath and go back and reread the posts. They are numerous, but substantiate themselves if you look at them chronologically. Sometimes printing them out helps, too, as compared to reading them quickly online.

 

[womble]

Please understand that I was not trying to be argumentative, just that there are IMHO a lot of different opinions about what and how to do things. I truly appreciate your help.
Thank you.

BTW, as to the nut ON the secondary fuel filter; there is no nut on ANY of the various filters that are recommended for the M25XP engine. Since so many folks say there is, what am I missing?

 

[Jim 5757]

I think the nut referred to is on the filter mount not the replaceable cartridge...

 

[womble]

Ah ha!!! I've never seen the nut - but then I was looking ON the filter!! Thank you.

 

[Jongleur]

My engine is one that has never needed to use the nut
on the filter mount for bleeding. The knurled knob
works just fine.

By the way, On my previous boat (K41 with M25XP)
I had a gravity feed day tank above the individually valved
2 parallel filters and engine. That system worked a
treat. Never had to bleed anything, ever.